Method of fabricating an integrated circuit package having a liquid metal-aluminum/copper joint

Abstract

An integrated circuit package includes an integrated circuit chip, a substrate which holds the chip, and a heat conduction mechanism which provides a path for conducting heat from the chip to a fluid medium; wherein the heat conduction mechanism is characterized as having a pressed joint which is comprised of: 1) a member that is made primarily of aluminum or copper, having a solid polysiloxane coating of less than 200Å thickness, and 2) a liquid metal alloy in contact with the coating. This solid coating, on the aluminum or copper member, is fabricated without any expensive equipment by the steps of: 1) forming a liquid coating of a polysiloxane solution on the aluminum or copper member; and 2) baking that member with its liquid coating at temperatures of 100° C.-300° C. for 0.5 hours-3.0 hours. Thereafter the integrated circuit package is completed by placing the member with its solid coat in the heat conducting path such that a liquid metal alloy is in contact with the solid coat.

What is claimed is: 
     
       1. A method of fabricating an integrated circuit package including the steps of: providing--1) a substrate, 2) an integrated circuit chip mounted on said substrate, and 3) a heat conduction mechanism which contains a gap coupled to said chip;   saturating a compliant body, having microscopic voids throughout, with a liquid metal alloy;   removing a substantial portion of said alloy from said compliant body such that all remaining alloy is held in said voids by surface tension and adhesive forces; and,   compressing said compliant body, with said remaining alloy, into said gap without squeezing said alloy out of said body.   
     
     
       2. A method according to claim 1 wherein said removing step includes squeezing said compliant body when said alloy is saturated therein. 
     
     
       3. A method according to claim 1 wherein said removing step includes centrifuging said compliant body when said alloy is saturated therein. 
     
     
       4. A method according to claim 1 wherein said removing step includes vacuuming said compliant body when said alloy is saturated therein. 
     
     
       5. A method according to claim 1 wherein said removing step includes shaking said compliant body when said alloy is saturated therein. 
     
     
       6. A method according to claim 1 wherein said removing step is performed such that films of said alloy remain at random locations in said body across said microscopic voids. 
     
     
       7. A method according to claim 6 and further including the substep of substantially shrinking said compliant body in thickness by said films. 
     
     
       8. A method of fabricating an integrated circuit package of the type which includes an integrated circuit chip, a substrate which holds said chip, and a heat conduction mechanism coupled to said chip which provides a path for conducting heat from said chip to a fluid medium; wherein said method includes the steps of: forming a liquid coating of a polysiloxane solution on a member which is made primarily of metal selected from the group of aluminum and copper;   baking said member with said liquid coating to thereby form a solid polysiloxane coat;   placing said member with said solid coat in said heat conducting path; and,   including a liquid metal in said heat conducting path such that said liquid metal is in contact with said solid coat.   
     
     
       9. A method according to claim 8 wherein said forming step includes the substep of dipping said member into said siloxane solution. 
     
     
       10. A method according to claim 8 wherein said forming step includes the substep of spraying said member with said polysiloxane solution. 
     
     
       11. A method according to claim 8 wherein said forming step includes the substep of painting said member with said polysiloxane solution. 
     
     
       12. A method according to claim 8 wherein said forming step includes the substep of spinning said member with said polysiloxane solution. 
     
     
       13. A method according to claim 8 wherein said baking step heats said aluminum member to temperatures of 100° C. to 300° C. 
     
     
       14. A method according to claim 8 wherein said polysiloxane solution, by volume, is 50%-100% polydimethylsiloxane. 
     
     
       15. A method according to claim 8 wherein said polysiloxane solution by volume, is 50%-100% polydimethyldiphynelsiloxane.